1. Field of the Invention
This invention relates to passive seatbelt systems and more particularly to passive seatbelt systems which automatically move the seatbelt to fasten and unfasten the seatbelt.
2. Prior Art
Since seatbelt systems restrain and protect passengers during vehicular emergencies, they contribute to the safety of the motor vehicle. In spite of this fact, however, the percentage of passengers who wear seatbelts is extremely low because of the difficulty in donning the seatbelt, a feeling of pressure when seatbelt is worn, etc.
As a result, passive seatbelt systems have been proposed which make it possible to automatically fasten the belt around the passenger after the passenger has seated himself in the vehicle. Such passive seatbelts are designed such that the driving force of a motor is used to move one end or an intermediate portion of the belt back and forth in the direction of the length of the vehicle. This causes the belt to alternately approach and move away from the passenger seat so that the space between the belt and the passenger alternately contracts and expands. In this way, the belt is automatically fastened around and removed from the passenger.
In such a passive seatbelt system, a wire is used as the tractive part in order to transmit the driving force of the motor to the belt. These systems using a wire require captans and pulleys and are very complex and expensive. In addition, the installation of these parts in the vehicle is difficult and extremely inefficient.